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Résultats de la recherche (122 résultats)

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  • Tropical rain forests
  • Biodiversity ; Biogeography ; Ecosystem ; Environmental degradation ; Forest ; Tropical rain forest
  • The A. reports on the progress in describing and explaining variation of biodiversity in tropical rain forests. He bases this review on a search of the 1997 editions of Ecology Abstracts, Ecological Abstracts and Forestry Abstracts.
  • 1998
  • The historic role of the forest community in sustaining the Black Hills National Forest as a complex common property multiple use resource
  • Environment ; Forest ; Mine ; Nature conservation ; Resource management ; Rural community ; South Dakota ; United States of America ; Wyoming
  • A common property resource must be defined, and throughout the history of the Black Hills National Forest (1898 forward), there has been a community of people interested in defining and redefining it as a resource. Four historical periods
  • are discussed : the gold mining community, building of a forest community (interested in maintening multiple uses), fragmentation of the forest community, and progress toward a multiple-use definition. - (SLD)
  • 1998
  • Forest protection in the Caraballo Sur, Northern Philippines
  • Environment ; Forest ; Nature conservation ; Philippines ; Resource management ; Rural community
  • Article presents a case of how an indigenous people can be empowered to ensure the survival of the forest on which they, in part, depend. In 1974, the Ikalahan/Kalanguya community in the Caraballo Sur Mountains of the Northern Philippines negotiated
  • an agreement with the state that gave them authority over ancestral forest lands. The resulting community-enforced rules have protected the forest and sanctions have made rule breakers make amends to the forest and to the community. - (SLD)
  • 1998
  • Heterogeneity of forest characteristics in primary and secondary forest stands on the third Chickasaw loess bluff, Tennessee
  • Analysis of variance ; Biodiversity ; Biogeography ; Ecology ; Forest ; Habitat ; Loess ; Spatial variation ; Tennessee ; United States of America
  • In this study, the AA. hypothesized that primary and secondary forest stands in western Tennessee would exhibit different patterns of heterogeneity. They contrasted non-spatial and spatial components of heterogeneity for a mid-successional forest
  • (55 years old) and an adjacent primary forest, using both direct and indirect measures. The nonspatial components included : the vertical complexity of the forests with respect to tree sizes/layers, a measure of species diversity, and the statistical
  • 1998
  • Forest diversity, distribution, and dynamique in the Itombwe Mountains, South-Kivu, Congo Democratic Republic
  • Biodiversity ; Deforestation ; Environmental conservation ; Forest ; Human impact ; Mountain
  • Paper begins with a detailed description of the Itombwe Mountains forest, near Lake Tanganyika, in the congo (formely Zaire), based on bibliographic review, landscape traverses in 1992-1993, and remote sensing data from 1980-1985. Author considers
  • these mountains to be the second most important, if not the most important, location of highland forests in continental Africa, with a very high level of biodiversity, wide range of vegetation types, and a wide range of forest types. Their conservation
  • 1998
  • Optical remote-sensing techniques for the assessment of forest inventory and biophysical parameters
  • Biogeography ; Canada ; Ecological inventory ; Ecosystem ; Environmental management ; Forest ; Image processing ; LANDSAT ; Remote sensing ; Thematic Mapper
  • This article provides a summary of the image-processing methods which may be applied to remotely sensed data for the estimation of forest structural parameters while also acknowledging the various limitations that are presented. This review
  • , with reference to forest structural parameters, illustrates the dependence between spatial resolution to the level of detail of the parameters which may be extracted from remotely sensed imagery. Further, the combination of spectral and spatial information
  • techniques shows promise for increasing the accuracy of estimates of forest inventory and biophysical parameters.
  • 1998
  • Defining degradation : the impacts of swidden on forests in Northern Thailand
  • Environment ; Environmental degradation ; Ethnic community ; Forest ; Land clearing ; Shifting cultivation ; Thailand ; Vegetation dynamics
  • A reevaluation of the usual view that shifting cultivation leads to forest degradation, soil erosion, water shortages, and other undesirable changes. Author examines the swidden farming near three upland villages in northern Thailand. swiddens
  • of the Lawa and Karen ethnic groups provided better land however, swidden of the one Akha village led to species loss and less economically useful secondary forest growth. - (SLD)
  • 1998
  • The politics of conservation and the complexity of local controls of forests in the Northern Thai Highlands
  • Environment ; Environmental conservation ; Forest ; Mountain ; Resource management ; Rural community ; Shifting cultivation ; Thailand
  • An analysis of recent state conservation policy and the complexities of local control of forest land in northern Thailand. Author holds that government agencies resist allowing ethnic minorities to have a role in conservation. The government
  • maintains that shifting cultivation has only a negative impact on the environment, disregarding the variety of local practices. The state has striven to extend its control over forests, and the implementation of the state's conservation policy has had many
  • 1998
  • Runoff and erosion processes after a forest fire in Mount Carmel, a mediterranean area
  • Forest fire ; Israel ; Mediterranean area ; Mountain ; Rill wash ; Sediment budget ; Soil erosion ; Water erosion
  • In the mediterranean forest area of Israel, fires increase runoff and sediment yield rates relative to undisturbed forested land. This study aims to : 1) determine the rates of water runoff and sediment yield from burnt slope sites, related
  • 1998
  • Absence of last glacial maximum records in lowlan tropical forests
  • Amazon Basin ; Brazil ; C 14 dating ; Lateglacial ; Lithology ; Mineralogy ; Palaeo-environment ; Palaeoclimate ; Palynology ; Quaternary ; Sedimentology ; Tropical rain forest
  • Environmental conditions of the lowland tropical forests during the last glacial maximum (LGM) between ca 20,000 and 18,000 C 14 yr B.P., are reevaluated in terms of dating control and lithology analyzed in seven pollen records from South America
  • 1998
  • Radiocarbon age of Holocene paleosols of the East European forest-steppe zone
  • C 14 dating ; Chernozem ; Eastern Europe ; European part of Russia ; Forest soil ; Holocene ; Organic materials ; Palaeo-environment ; Palaeosol ; Pedogenesis ; Plain ; Ukraine ; Volga
  • This paper evaluates differences in the radiocarbon ages of surface and buried humus horizons of the East European forest-steppe zone, to estimate the rate of organic matter turnover in polygenetic soils, and to determine the periods of different
  • 1998
  • The forest sector of the Russian Far East
  • Asian part of Russia ; Data ; Eastern Siberia ; Export ; Forecast ; Forest ; Forest resources ; Logging ; Resource management ; Stand treatment ; Wood
  • 1998
  • Estimates of current and historical fluxes of N, Ca, and K in the forest ecosystem Möhlin
  • Basel ; Biomass ; Ecosystem ; Forest ; Geochemistry ; Human impact ; Humus ; Soil ; Soil properties ; Soil water ; Switzerland
  • them with current fluxes measured in the period 1992-1994. The influence of forest management on element fluxes seems to be substantial, especially on the fluxes of base cations, but can be reduced with simple measures (e.g. removal of the bark
  • 1998
  • Bibliography ; Climatology ; Forest ; Microclimate ; Model ; Simulation ; Urban climate
  • advances in the understanding of the climates and climatic processes particular to two landscapes types, urban areas and forested regions.
  • 1998
  • Fire history of mixed-conifer forests on the North Rim, Grand Canyon National Park, Arizona
  • Altitude ; Arizona ; Biogeography ; Canyon ; Dendrochronology ; Dendrology ; Ecotone ; Forest ; Forest fire ; Historical geography ; United States of America ; Vegetation dynamics
  • This study uses dendrochronology and historical fire records to determine the fire history of mixed-conifer forests along an elevation and temporal gradient. The research constitutes a component of a broader mixed-conifer project that investigates
  • 1998
  • The effects of forest diching and water level changes on sediment quality in a small lake, Perhonlampi, Central Finland
  • and sedimentological changes are caused by forest ditchings at 1971 and 1980.
  • 1998
  • Ain ; Channel geometry ; Floodplain ; Forest ; France ; Meander ; Piedmont ; Riparian vegetation ; Statistics ; Stream
  • largely by riparian forest vegetation. The total LWD deposited along concavities was most strongly controlled by meander-bend geometry. Findings from this study are applicable to restore alluvial forests along French rivers.
  • 1998
  • Holocene history of the Chocó rain forest from Laguna Piusbi, southern Pacific lowlands of Colombia
  • Biodiversity ; C 14 dating ; Colombia ; Ecosystem ; Holocene ; Human impact ; Lacustrine sediment ; Palaeo-environment ; Palaeobiogeography ; Palynology ; Pollen diagram ; Tropical rain forest
  • 1998
  • Arid area ; Atmospheric circulation ; Bibliography ; Climatology ; Energy balance ; Forest ; Mesoclimate ; Microclimate ; Periglacial features ; Semi-arid area ; Tundra ; Urban climate
  • This survey is limited to 3 themes prevalent in research published in 1996 : land-surface heterogeneity, mesoscale circulations, and the energy budgets and microclimates of 4 particular surface classes (forests, arid and semi-arid areas, urban areas
  • 1998
  • Arid area ; Bibliography ; Deforestation ; Forest ; Forestry ; Nature conservation ; Rural development ; Tropical rain forest ; Tropical zone
  • 1998